title: Precise resection and biological reconstruction under navigation guidance for young patients with juxta-articular bone sarcoma in lower extremity: preliminary report.
abstract: BACKGROUND
  It is a challenge to perform a joint-preserving resection for young patients with juxta-articular bone sarcomas. We determined whether osteotomy under image-guided navigation make joint-saving resection possible for juxta-articular lesions while adhering oncological principles.
  
  
  METHODS
  Between June 2008 and July 2010, joint-preserving limb salvage surgeries were performed on 9 patients with juxta-articular bone sarcomas under navigation guidance. Computed tomography/magnetic resonance imaging fusion images were used for real-time navigation. Eight lesions located around the knee and 1 in hip. Six tumors extend to and 3 beyond the epiphyseal line. Planned osteotomy under image-guided navigation was employed for achieving clear surgical margin while maximizing host tissue preservation. All tumors were en bloc removed and intercalary defect were reconstructed by combination of allograft with vascularized fibula graft. All specimens were examined for resection margin. Patients were followed up for an average of 25.2 months for evaluating of functional and oncology outcomes.
  
  
  RESULTS
  Entire joint were preserved in 6 patients and part of joint were saved in another 3 patients. The mean registration error for navigation was 0.40 mm (range, 0.31 to 0.62 mm). Clear surgical margin was obtained in all specimens. The average closest distance between the osteotomy line and tumor edge was 9.6 mm (range, 6 to 14 mm). Entire joint cartilage was preserved in 6 patients and portion of joint were saved in 3 patients (2 in proximal tibia, 1 in distal femur). No patient experienced local recurrence. Two patients developed lung metastasis. One died of disease and the other underwent metastasectomy and had no evidence of disease at the most recent follow-up. All reconstruction was in situ with the Musculoskeletal Tumor Society average score of 26.7 at final follow-up.
  
  
  CONCLUSIONS
  With careful patient selection, image navigation-assisted surgery made it possible to resect the bone exactly as planned in length and orientation in the magnetic resonance imaging image, yielding a clear margin and preserving the entire or part of the articular cartilage in joint-sparing limb salvage procedures for treating skeletally immature patients with juxta-articular bone sarcomas.
  
  
  METHODS
  Level IV--therapeutic study.
authors.affiliation: Department of Orthopaedic Oncology, Xi Jing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Guo
authors.forename: Guo-Jing
authors.initials: GJ
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
authors.forename: Guo-Xian
authors.initials: GX
authors.lastname: Pei
mesh_terms: D000293:Adolescent; D001859:Bone Neoplasms / Q000175:diagnosis / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000473:pathology / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000473:pathology / Q000601:surgery; D023821:Limb Salvage / Q000379:methods*; D035002:Lower Extremity / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009367:Neoplasm Staging; D018217:Osteosarcoma, Juxtacortical / Q000175:diagnosis / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D019651:Plastic Surgery Procedures / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D018570:Risk Assessment; D025321:Surgery, Computer-Assisted / Q000009:adverse effects / Q000379:methods*; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D055815:Young Adult